The present invention relates to an imaging and obstacle detection system for assisting a pilot in controlling an aircraft or other vehicle, of the type which includes both a natural vision low light amplifier and a range imaging system.
In order to assure detection of obstacles which may endanger the pilot of a low-flying aircraft or of a vehicle, natural vision, low-light amplifiers or night-viewing devices are frequently not sufficient. High-resolution, laser radar based range imaging sensors supply additional obstacle information. The objective of such a system is to analyze and represent this additional information in an ergonomically optimal manner within the scope of an overall obstacle warning system for manually flying pilots. In this regard, a particularly important class of obstacles are wires or lines.
In previously known systems of this type, information generated by the range imaging system is analyzed or classified and used to generate alphanumeric or symbolic displays which alert the pilot to the location of detected obstacles. Such prior art systems, however, require substantial computer processing expenditures and result in high data rates at the output of the analyzing computer. Moreover, if such alphanumeric or symbolic displays are superimposed on the basic image generated by the natural vision observation system, they necessarily block out a portion of the image. Furthermore, because the alphanumeric display or symbols represent information which is in addition to the image generated by the basic natural vision system, their assimilation by the pilot requires a separate cognitive process which necessarily diverts his or her attention at least momentarily from the basic image, to an assessment of the significance of the alphanumeric or graphic display.
An object of the invention is to provide a system for assisting the pilot of a low flying aircraft in the detection and recognition of obstacles, which system requires a minimal amount of computer processing, and presents information to the pilot in an ergonomically optimum manner, in that the information is easily assimilated by the pilot.
This object is achieved by the system according to the invention, in which information generated by a range imaging sensor is processed to extract therefrom a graphic display depicting the linear edge contours of detected obstacles, which display is then blended into the basic image of the natural vision system.
On the basis of the characteristics of the invention, the following advantages are achieved:
Optimal ergonomy by means of a graphic (not symbolic) display of the obstacles. A human being can make a classification much more easily on the basis of contours of an object than any algorithm. Therefore, obstacle contours are the graphically "most economical" device for displaying obstacles without any significant loss of information. This leads to low data rates at the output of the analyzing computer and to a minimal hiding of the basic image by additional obstacle information.
The method for extracting the contours utilizes the information content of the range image in an optimal manner. This results in simple algorithms which also operate robustly in the case of complex obstacle scenes and in a lower computing performance required at the analyzing computer.
For range image sensors whose imaging rate is below 25 Hz, a method for a synchronization with the basic image can be provided, which does not require navigational data.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.